1. Field of the Invention
The present invention relates to a projection-type display apparatus and a geometric distortion correcting method.
2. Description of the Related Art
Japanese Patent Laid-Open No. (“JP”) 2005-123669 discloses a projection-type display apparatus configured to perform Keystone distortion correction, for an input image having an aspect ratio different from that of a display device (liquid crystal panel), by enlarging its horizontal or vertical length. This projection-type display apparatus can prevent dropping of the vertical or horizontal resolution and maintain the image quality.
However, in JP 2005-123669, the enlargement ratio is different according to input images, and thus even when a certain input image is adjusted so that its projected image can be displayed on a predefined area of a projection surface, the projected image of another input image overflows the predefined area. In this case, even when a position and an attitude of the projection-type display apparatus are fixed, it is necessary to readjust a zoom and a distortion correcting amount, lowering the operability.